13 Sep
2004
13 Sep
'04
2:28 p.m.
Mikhail,
I downloaded the original and c0 versions of your WAV files. I could
hear only very little difference between these files, and it took many,
many repeated plays to hear any difference at all. I heard nothing of
the sort you mentioned (ringing and "very distorted"). I am using a
sound card that runs at 48,000 samples/sec and 44,100 samples/sec, and
I verified that the clock was actually switching. (It also does
96,000 --- ICE 1712 type chipset).
I also used my own resampler (FFT overlap type) and heard no difference
between the original and that one. So all three sounded almost identical
to me, but not quite. There was a teensy-weensy difference with the sinc-
based one, but it actually sounded a teensy-weensy bit better, not worse!
I also listened with speakers and two different style headphones, including
one studio monitor type.
I agree with Erik that this ringing and distortion must come from your
sound card or driver setup and additional sample-rate conversions or
something like that, not from the sinc-based resampling. I am not a
big fan of sinc-based resampling for fixed-rate conversions, so I would
tell you if there was anything bad. I don't hear anything unacceptable
at all --- other than that the source is very noisy! That's going to
be hard to clean without noticeable artifacts based on some cleaning
I've done in the past (Windows-based, not Linux). So I wish you good
luck.
Best regards,
Dave.
13 Sep
13 Sep
3:10 p.m.
New subject: [linux-audio-user] hard disk solved, but...
Hi!
Thats me again, brazilian with a lot of xruns.
My hard disk is OK now. The transfer rate go out of 3MB/sec and now I have
50MB/sec.
Seems a good transfer rate.
BUt I continue with xruns runing jackd.
I saw something about patches for kernel 2.6.8.
I downloaded source kernel 2.6.8 and now I'll compile it.
But I don't have any idea about real necessarily of this patches and I
don't know where can I get that patches.
Somebody can help me?
THanks a lot again!
Alexander
Brazil - Rio de Janeiro
3:24 p.m.
New subject: [linux-audio-user] hard disk solved, but...
On Mon, 13 Sep 2004 12:43:29 -0300 (BRT)
Alexander Franca <alexander(a)edem.g12.br> wrote:
Hi!
Thats me again, brazilian with a lot of xruns.
My hard disk is OK now. The transfer rate go out of 3MB/sec and now I
have 50MB/sec.
Seems a good transfer rate.
BUt I continue with xruns runing jackd.
I saw something about patches for kernel 2.6.8.
I downloaded source kernel 2.6.8 and now I'll compile it.
But I don't have any idea about real necessarily of this patches and I
don't know where can I get that patches.
Somebody can help me?
Hi,
i didn't follow this thread but are you maybe a victim of NPTL hell?
http://www.affenbande.org/~tapas/wiki/index.php?Jackd%20and%20NPTL
flo
6:26 p.m.
On Mon, 13 Sep 2004 11:11:20 -0700
davidrclark(a)earthlink.net wrote:
I also used my own resampler (FFT overlap type) and
heard no difference
between the original and that one. So all three sounded almost identical
to me, but not quite. There was a teensy-weensy difference with the sinc-
based one, but it actually sounded a teensy-weensy bit better, not worse!
Yeeee Haaaaaa!!!! :-).
Erik
--
+-----------------------------------------------------------+
Erik de Castro Lopo nospam(a)mega-nerd.com (Yes it's valid)
+-----------------------------------------------------------+
I have found that good programmers either do not make the kind
of mistakes that Ada can prevent, or insert enough checks that
they catch those mistakes about as efficiently as an Ada
environment can. At that point, the use of Ada gives no further
productivity advantage.
14 Sep
14 Sep
6:37 a.m.
davidrclark(a)earthlink.net wrote:
I also used my own resampler (FFT overlap type) and
heard no difference
between the original and that one. So all three sounded almost identical
to me, but not quite. There was a teensy-weensy difference with the sinc-
based one, but it actually sounded a teensy-weensy bit better, not worse!
I also listened with speakers and two different style headphones, including
one studio monitor type.
Thanks. It was the playback.
Is your resampler published? I'd like to try it. Since the resampling
turned out to be possible, I will probably use this setup for Vinyl->CD
conversion; and I'd like to have as good a resampler as possible.
I agree with Erik that this ringing and distortion
must come from your
sound card or driver setup and additional sample-rate conversions or
something like that, not from the sinc-based resampling. I am not a
big fan of sinc-based resampling for fixed-rate conversions, so I would
tell you if there was anything bad. I don't hear anything unacceptable
at all --- other than that the source is very noisy! That's going to
be hard to clean without noticeable artifacts based on some cleaning
I've done in the past (Windows-based, not Linux). So I wish you good
luck.
The source is very noisy because that particular recording is a
grammophone one made around 1930, then copied with some cleaning to new
vinyl around 1980. It's DOUBLE mechanical recording noise.
Yours, Mikhail Ramendik
7:46 a.m.
On Tue, 14 Sep 2004 14:20:44 +0400
Mikhail Ramendik <mr(a)ramendik.ru> wrote:
Thanks. It was the playback.
Is your resampler published? I'd like to try it. Since the resampling
turned out to be possible, I will probably use this setup for Vinyl->CD
conversion; and I'd like to have as good a resampler as possible.
But he already said that libsamplerate (as used by sndfile-resample)
sounded better!!!!!
Erik :-)
--
+-----------------------------------------------------------+
Erik de Castro Lopo nospam(a)mega-nerd.com (Yes it's valid)
+-----------------------------------------------------------+
"Always code as if the person who ends up maintaining your
code will be a violent psychopath who knows where you live."
-- Martin Golding
--
+-----------------------------------------------------------+
Erik de Castro Lopo nospam(a)mega-nerd.com (Yes it's valid)
+-----------------------------------------------------------+
"I want to make sure (a user) can't get through ... an online
experience without hitting a Microsoft ad."
- Microsoft CEO, Steve Ballmer on the Microsoft search engine.
8:32 a.m.
I am posting this to the list because I am pretty sure that
Mikhail intended to reply to the list rather than directly
to me. I also think the explanation below will be useful
for others.
On Tue, 14 Sep 2004 15:49:36 +0400
Mikhail Ramendik <mr(a)ramendik.ru> wrote:
This probably means that the libsamplerate resampler
kills off higher
frequencies.
Lowpass filtering is an absolute MUST when doing sample rate
reduction (ie 48kHz to 44.1kHz like you are doing). Failure to
low pass filter results in audio artifacts which you will hear
on source material without too much background noise.
That said, libsamplerate applies the absolute minimum lowpass
filtering possible. For instance, with the highest quality
converter provided by libsamplerate, the bandwidth (measured
from 0Hz to the frequency where the lowpass filter has its
-3dB point) is 96.6% of the theoretical best bandwidth. For
a source sample rate of 48kHz and a destination sample rate
of 44.1kHz, the -3dB point would be:
0.966 * 0.5 * 44100 = 21300 Hz
I think you will agree that this lowpass filter will not kill
off any frequencies that you can hear unless you happen to be
a dog :-).
When encoding this same source to MP3, I found that it
sounds better
with frequencies above 16 khz suppressed (with lame --lowpass). The
better sound of libsamplerate is probably of the same nature.
That is a completely different situation and not a valid comparison.
If I get to encode better recordings, I might not want
a lowpass filter
If you fail to lowpass filter before downsampling you WILL get
a crappy sound output.
Erik
--
+-----------------------------------------------------------+
Erik de Castro Lopo nospam(a)mega-nerd.com (Yes it's valid)
+-----------------------------------------------------------+
"Windows was created to keep stupid people away from UNIX."
-- Tom Christiansen
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linux-audio-user@lists.linuxaudio.org
6 comments
5 participants
participants (5)
-
Alexander Franca -
davidrclark＠earthlink.net -
Erik de Castro Lopo -
Florian Schmidt -
Mikhail Ramendik